Impact of impulse voltage frequency on the partial discharge characteristic of electric vehicles motor insulation

The urgent need for electric vehicles is the leading research to safer operation of electric motors on high frequency impulsive voltages. For low voltage electric vehicles partial discharge (PD) inception voltage tests under impulse voltage waveforms are desired. However, measuring PD using repetitive impulse waveforms is critical in selecting generators with appropriate parameters to increase PD detection sensitivity. Here, we report on PD characteristics for such kind of voltage waveforms, demonstrated with the high frequency and thermal impact on different types of motor insulation models. The increasing frequency of impulsive voltages tends to result in PD activities with low magnitude and short delay times. In this case, some PD pulses are missed because the PD and disturbance pulses produced by power electronic devices will likely overlap. Therefore, these parameters are carefully considered to evaluate the insulation performance of EV motors.